It could be that Mister Sinister’s alter ego, Nathaniel Essex, will be appearing in a pre-Mister Sinister format in Wolverine 3, perhaps leading to a full on Mister Sinister appearance in a future X-Men film.
Wolverine 3 aims to send Jackman’s Wolvie off in a blaze of glory. On top of that, Bryan Singer had indicated that classic X-Men villain Mister Sinister will appear in the film.
However, Wolverine 3 director James Mangold (who also helmed 2013’s The Wolverine) is playing a different game for the time being.
After all, the post-credits scene from X-Men: Apocalypse has already confirmed the existence of Essex Corp, the company run by Mister Sinister, as part of the X-Men cinematic universe.